U.S. patent application number 15/504590 was filed with the patent office on 2017-08-17 for three-dimensional thin film battery.
This patent application is currently assigned to APPLIED MATERIALS, INC.. The applicant listed for this patent is APPLIED MATERIALS, INC.. Invention is credited to Byung Sung Leo KWAK, Daoying SONG.
Application Number | 20170237124 15/504590 |
Document ID | / |
Family ID | 59559784 |
Filed Date | 2017-08-17 |
United States Patent
Application |
20170237124 |
Kind Code |
A1 |
SONG; Daoying ; et
al. |
August 17, 2017 |
THREE-DIMENSIONAL THIN FILM BATTERY
Abstract
A thin film battery may comprise: a substrate comprising a
substrate surface; a first current collector (FCC) layer formed on
the substrate surface, the FCC layer having a first FCC surface and
a second FCC surface and wherein the first FCC surface is in
contact with the substrate and the second FCC surface is a first
three-dimensional surface; a first electrode layer deposited on the
first current collector, and an electrolyte layer deposited on the
first electrode layer; wherein the interface between the first
electrode layer and the electrolyte layer is a second
three-dimensional surface roughly in conformity with the first
three-dimensional surface. In embodiments, the substrate surface is
a third three-dimensional surface and the first three-dimensional
surface is roughly in conformity with the third three-dimensional
surface. One of the first or the third three-dimensional surfaces
may be formed by a laser ablation patterning process.
Inventors: |
SONG; Daoying; (San Jose,
CA) ; KWAK; Byung Sung Leo; (Portland, OR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
APPLIED MATERIALS, INC. |
Santa Clara |
CA |
US |
|
|
Assignee: |
APPLIED MATERIALS, INC.
Santa Clara
CA
|
Family ID: |
59559784 |
Appl. No.: |
15/504590 |
Filed: |
August 27, 2015 |
PCT Filed: |
August 27, 2015 |
PCT NO: |
PCT/US15/47286 |
371 Date: |
February 16, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62042577 |
Aug 27, 2014 |
|
|
|
Current U.S.
Class: |
429/162 |
Current CPC
Class: |
H01M 4/0407 20130101;
H01M 4/134 20130101; H01M 4/382 20130101; H01M 6/40 20130101; H01M
10/0585 20130101; H01M 4/1391 20130101; H01M 4/70 20130101; H01M
4/0426 20130101; H01M 10/0562 20130101; H01M 10/0525 20130101; H01M
2300/0068 20130101; H01M 10/052 20130101; H01M 4/0404 20130101;
H01M 4/131 20130101; H01M 4/1395 20130101; H01M 4/525 20130101;
H01M 2004/021 20130101; Y02E 60/10 20130101; H01M 4/0471
20130101 |
International
Class: |
H01M 10/0585 20060101
H01M010/0585; H01M 4/04 20060101 H01M004/04; H01M 4/131 20060101
H01M004/131; H01M 4/1391 20060101 H01M004/1391; H01M 10/0562
20060101 H01M010/0562; H01M 4/1395 20060101 H01M004/1395; H01M
4/525 20060101 H01M004/525; H01M 4/38 20060101 H01M004/38; H01M
10/0525 20060101 H01M010/0525; H01M 4/70 20060101 H01M004/70; H01M
4/134 20060101 H01M004/134 |
Claims
1. A thin film battery, comprising: a substrate comprising a
substrate surface; a first current collector (FCC) layer formed on
said substrate surface, said FCC layer having a first FCC surface
and a second FCC surface and wherein said first FCC surface is in
contact with said substrate and said second FCC surface is a first
three-dimensional surface; a first electrode layer deposited on
said first current collector, and an electrolyte layer deposited on
said first electrode layer; wherein the interface between said
first electrode layer and said electrolyte layer is a second
three-dimensional surface roughly in conformity with said first
three-dimensional surface.
2. The thin film battery of claim 1, wherein said first
three-dimensional surface comprises an array of patterned
shapes.
3. The thin film battery of claim 1, wherein said substrate surface
is a third three-dimensional surface and said first
three-dimensional surface is roughly in conformity with said third
three-dimensional surface.
4. The thin film battery of claim 1, further comprising: a second
electrode layer deposited on said electrolyte layer; and a second
current collector (SCC) layer deposited on said second electrode
layer; wherein said electrolyte layer is deposited on said first
electrode layer and wherein the interface between said second
electrode layer and said electrolyte layer is a fourth
three-dimensional surface roughly in conformity with said first
three-dimensional surface.
5. The thin film battery of claim 4, wherein the interface between
said second electrode layer and said SCC layer is a fifth
three-dimensional surface roughly in conformity with said fourth
three-dimensional surface.
6. The thin film battery of claim 1, wherein said FCC layer is a
cathode current collector layer and said first electrode layer is a
cathode layer.
7. The thin film battery of claim 1, wherein said FCC layer is an
anode current collector layer and said first electrode layer is an
anode layer.
8. The thin film battery of claim 4, wherein said FCC layer is a
cathode current collector layer and said first electrode layer is a
cathode layer, and wherein said second electrode layer is an anode
and said SCC layer is an anode current collector layer.
9. The thin film battery of claim 4, wherein said FCC layer is an
anode current collector layer and said first electrode layer is an
anode layer, and wherein said second electrode layer is a cathode
and said SCC layer is a cathode current collector layer.
10. A method of manufacturing a thin film battery, comprising:
providing a substrate; three-dimensionally restructuring the
surface of said substrate to form a restructured substrate surface;
depositing a first current collector (FCC) layer on said
restructured substrate surface; depositing an electrode layer on
said FCC layer; and depositing an electrolyte layer on said
electrode layer; wherein the interface between said electrode layer
and said electrolyte layer is a first three-dimensional surface
roughly in conformity with said restructured substrate surface.
11. The method of claim 10, further comprising: depositing a second
electrode layer on said electrolyte layer; wherein the interface
between said electrolyte layer and said second electrode layer is a
second three-dimensional surface roughly in conformity with said
restructured substrate surface.
12. A method of manufacturing a thin film battery, comprising:
providing a substrate; depositing a first current collector (FCC)
layer on the surface of said substrate; three-dimensionally
restructuring the surface of said FCC layer to form a restructured
FCC surface; depositing a first electrode layer on said
restructured FCC surface; and depositing an electrolyte layer on
said first electrode layer; wherein the interface between said
first electrode layer and said electrolyte layer is a first
three-dimensional surface roughly in conformity with said
restructured FCC surface.
13. The method of claim 10, wherein said three-dimensionally
restructuring comprises a laser ablation patterning process.
14. The method of claim 12, wherein said three-dimensionally
restructuring comprises a mechanical roughening process.
15. The method of claim 12, further comprising: depositing a second
electrode layer on said electrolyte layer; wherein the interface
between said electrolyte layer and said second electrode layer is a
second three-dimensional surface roughly in conformity with said
restructured first current collector surface.
16. The method of claim 12, wherein said three-dimensionally
restructuring comprises a laser ablation patterning process.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 62/042,557 filed Aug. 27, 2014.
FIELD
[0002] Embodiments of the present disclosure relate generally to
thin film batteries and methods of making the same, and more
specifically, although not exclusively, to thin film batteries with
the surface of one of the substrate and cathode current collector
being three-dimensionally restructured by a laser process.
BACKGROUND
[0003] Thin film batteries (TFBs) may comprise a thin film stack of
layers including current collectors, a cathode (positive
electrode), a solid state electrolyte and an anode (negative
electrode). A TFB is generally fabricated as a two dimensional (2D)
device and the battery performance (e.g., rate capability and
capacity utilization) is limited by the surface area of the
cathode-electrolyte and anode-electrolyte interfaces through which
Li must diffuse during the intercalation/deintercalation processes.
Furthermore, TFBs are known to exhibit peeling/delamination at
various interfaces and at various stages of fabrication and
operation, such as after cathode annealing, after electrolyte
deposition, after anode deposition, after encapsulation deposition,
or during battery cycle testing.
[0004] Clearly, there is a need for TFB structures and methods of
manufacture that induce greater adhesion strength between layers in
the TFB stack, and provide a larger interfacial surface area
between the cathode and the electrolyte and/or the anode and the
electrolyte in order to improve battery performance.
SUMMARY
[0005] Some embodiments of the present disclosure relate to thin
film batteries (TFBs) with the surface of one of the substrate and
current collector being three-dimensionally restructured by a laser
process during battery thin film stack fabrication, followed by
depositions of subsequent layers such that the interfacial contact
area between the cathode/anode and the electrolyte is a
three-dimensional surface roughly in conformity with the
three-dimensionally restructured surface of the substrate/current
collector. The resulting three-dimensionally structured interfaces
between the cathode/anode layer(s) and the electrolyte layer are
expected to improve TFB performance (e.g., rate capability and
capacity utilization) and increase adhesion strength between layers
within the TFB stack sufficiently to reduce peeling/delamination,
when compared with a TFB stack having planar interfacial
layers.
[0006] According to some embodiments, a thin film battery may
comprise: a substrate comprising a substrate surface; a first
current collector (FCC) layer formed on the substrate surface, the
FCC layer having a first FCC surface and a second FCC surface and
wherein the first FCC surface is in contact with the substrate and
the second FCC surface is a first three-dimensional surface; a
first electrode layer deposited on the first current collector, and
an electrolyte layer deposited on the first electrode layer;
wherein the interface between the first electrode layer and the
electrolyte layer is a second three-dimensional surface roughly in
conformity with the first three-dimensional surface. Furthermore,
in embodiments, the substrate surface is a third three-dimensional
surface and said first three-dimensional surface is roughly in
conformity with said third three-dimensional surface.
[0007] According to some embodiments, a method of making the thin
film battery may comprise: providing a substrate;
three-dimensionally restructuring the surface of the substrate to
form a restructured substrate surface; depositing a first current
collector (FCC) layer on the restructured substrate surface;
depositing an electrode layer on the FCC layer; and depositing an
electrolyte layer on the electrode layer; wherein the interface
between the electrode layer and the electrolyte layer is a first
three-dimensional surface roughly in conformity with the
restructured substrate surface.
[0008] According to some further embodiments, a method of making
the thin film battery may comprise: providing a substrate;
depositing a first current collector (FCC) layer on the surface of
the substrate; three-dimensionally restructuring the surface of the
FCC layer to form a restructured FCC surface; depositing a first
electrode layer on the restructured FCC surface; and depositing an
electrolyte layer on the first electrode layer; wherein the
interface between the first electrode layer and the electrolyte
layer is a first three-dimensional surface roughly in conformity
with the restructured FCC surface.
[0009] According to some embodiments, an apparatus for
manufacturing TFBs according to some embodiments may include: a
first system for three-dimensionally restructuring the surface of a
substrate to form a restructured substrate surface; a second system
for depositing a first current collector (FCC) layer on the
restructured substrate surface; a third system for depositing an
electrode layer on the FCC layer; and a fourth system for
depositing an electrolyte layer on the electrode layer; wherein the
interface between the electrode layer and the electrolyte layer is
a first three-dimensional surface roughly in conformity with the
restructured substrate surface. The first system may comprise, for
example, a laser ablation patterning system, in embodiments an ion
sputtering system, and in embodiments a mechanical roughening
system (such as a bead blaster).
[0010] According to some further embodiments, an apparatus for
manufacturing TFBs according to some embodiments may include: a
first system for depositing a first current collector (FCC) layer
on the surface of a substrate; a second system for
three-dimensionally restructuring the surface of the FCC layer to
form a restructured FCC surface; a third system for depositing a
first electrode layer on the restructured FCC surface; and a fourth
system for depositing an electrolyte layer on the first electrode
layer; wherein the interface between the first electrode layer and
the electrolyte layer is a first three-dimensional surface roughly
in conformity with the restructured FCC surface. The second system
may comprise, for example, a laser ablation patterning system, in
embodiments an ion sputtering system, and in embodiments a
mechanical roughening system (such as a bead blaster).
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] These and other aspects and features of the present
disclosure will become apparent to those ordinarily skilled in the
art upon review of the following description of specific
embodiments in conjunction with the accompanying figures,
wherein:
[0012] FIG. 1A is a cross-sectional representation of a thin film
battery including a restructured substrate with a
three-dimensionally restructured substrate surface, according to
some embodiments;
[0013] FIG. 1B shows a perspective view of the restructured
substrate of FIG. 1A.
[0014] FIG. 2 is a flow chart for fabrication of a thin film
battery with a restructured substrate with a three-dimensionally
restructured surface, according to some embodiments;
[0015] FIG. 3 is a cross-sectional representation of a thin film
battery including a restructured cathode current collector with a
three-dimensionally restructured collector surface, according to
some embodiments;
[0016] FIG. 4 is a flow chart for fabrication of a thin film
battery including a restructured cathode current collector with a
three-dimensionally restructured collector surface, according to
some embodiments;
[0017] FIG. 5 is a schematic illustration of a cluster tool for TFB
fabrication, according to some embodiments;
[0018] FIG. 6 is a representation of a TFB fabrication system with
multiple in-line tools, according to some embodiments; and
[0019] FIG. 7 is a representation of an in-line tool of FIG. 6,
according to some embodiments.
DETAILED DESCRIPTION
[0020] Embodiments of the present disclosure will now be described
in detail with reference to the drawings, which are provided as
illustrative examples of the disclosure so as to enable those
skilled in the art to practice the disclosure. Notably, the figures
and examples below are not meant to limit the scope of the present
disclosure to a single embodiment, but other embodiments are
possible by way of interchange of some or all of the described or
illustrated elements. Moreover, where certain elements of the
present disclosure can be partially or fully implemented using
known components, only those portions of such known components that
are necessary for an understanding of the present disclosure will
be described, and detailed descriptions of other portions of such
known components will be omitted so as not to obscure the
disclosure. In the present specification, an embodiment showing a
singular component should not be considered limiting; rather, the
disclosure is intended to encompass other embodiments including a
plurality of the same component, and vice-versa, unless explicitly
stated otherwise herein. Moreover, applicants do not intend for any
term in the specification or claims to be ascribed an uncommon or
special meaning unless explicitly set forth as such. Further, the
present disclosure encompasses present and future known equivalents
to the known components referred to herein by way of
illustration.
[0021] Some embodiments of the present disclosure relate to thin
film batteries (TFBs) with the surface of one of the substrate and
cathode current collector (CCC) being three-dimensionally
restructured by a laser process during battery thin film stack
fabrication, followed by depositions of subsequent layers such that
the interfacial contact area between the cathode and the
electrolyte is a three-dimensional surface roughly in conformity
with the three-dimensionally restructured surface of the
substrate/CCC. Furthermore, in some embodiments the
electrolyte-anode and anode-ACC interfaces may also be three
dimensional surfaces roughly in conformity with the
three-dimensionally restructured surface of the restructured
substrate/CCC. The resulting three-dimensionally structured
interfaces between the cathode layer and the electrolyte layer and
the electrolyte layer and the anode layer are expected to improve
TFB performance (e.g., rate capability and capacity utilization,
especially at higher rates of charging/discharging) and improve
interfacial adhesion of layers within the TFB stack sufficiently to
reduce peeling/delamination, when compared with a TFB stack having
planar interfacial layers. (Roughening of interfaces between layers
induces "mechanical wrapping" at the interface for greater adhesion
strength.) Moreover, the three-dimensionally structured interface
between the cathode layer and the electrolyte layer is expected to
increase access to the (003) planes in the polycrystalline grain
structures in a LiCoO.sub.2 cathode layer at the interface, which
reduces resistance to lithium intercalation/deintercalation during
battery usage.
[0022] FIGS. 1A & B show an example of a TFB with a vertical
stack fabricated according to embodiments of the present disclosure
with a three-dimensionally restructured substrate surface. In FIG.
1A, the vertical stack comprises: a restructured substrate 110, the
substrate surface having been three-dimensionally restructured by a
laser process; a cathode current collector 120 deposited on the
surface of the restructured substrate; a cathode layer 130
deposited on the cathode current collector; an electrolyte layer
140 deposited on the cathode layer; an anode layer 150 deposited on
the electrolyte layer; and an anode current collector (ACC) 160
deposited on the anode layer. It should be noted that the
interfaces between the CCC and the cathode layer and between the
cathode layer and the electrolyte layer are three-dimensional
surfaces roughly in conformity with the three-dimensionally
restructured surface of the restructured substrate. Herein the term
"roughly in conformity with" is used to specify that a surface of a
deposited layer reproduces the general shape of the
three-dimensionally restructured surface due to the layer or layers
between the three-dimensionally restructured surface and the
surface in question each providing complete coverage but having a
layer thickness covering the sidewalls and bottom surfaces of
features in the three-dimensionally restructured surface which is
less than the layer thickness covering surviving portions of the
original surface and field areas. Furthermore, in some embodiments
the electrolyte-anode and anode-ACC interfaces may also be three
dimensional surfaces roughly in conformity with the
three-dimensionally restructured surface of the restructured
substrate--as shown in FIG. 1A. The TFB may also include protective
coating(s) and electrical contacts, for example. The perspective
view of FIG. 1A shows an array of conically shaped features 115
(such as truncated cones) on the restructured surface of the
substrate 110, although the features of the restructured substrate
surface may be varied in size, shape, spacing and arrangement from
what is shown. The features may include cylindrically-shaped
features, trapezoidally-shaped features, spherically-shaped
features, vias, trenches, and round depressions, for example; to
achieve satisfactory step coverage in vias and trenches, positively
reentrant shapes (width or diameter at the top is larger than that
at the bottom of the features) may be utilized. Feature sizes (as
determined in a plane parallel to the original surface of the
substrate) may be a few microns to tens of microns. Furthermore,
these features may be positioned in regular arrays--a square
lattice, for example--and in embodiments these features may be
positioned randomly. The density of features may be varied
widely--the highest densities corresponding to close-packed arrays.
In embodiments, greater than 50 percent of the substrate or CC
surface is restructured by forming features as described herein.
The depth (measured in the direction perpendicular to the original
surface of the substrate) of features will be limited by the
substrate thickness--a limit of 75% of the substrate thickness
being a reasonable upper limit, although this may be varied as
needed to maintain the mechanical integrity of the substrate.
Furthermore, in embodiments the depth of features is greater than
or equal to 25 percent of the substrate thickness. Furthermore, in
embodiments the depth of features is greater than or equal to 5
microns. For example, a 20 micron thick substrate may in
embodiments have features with depths within the range of greater
than or equal to 5 microns and less than 15 microns.
[0023] FIG. 2 provides a process flow, according to some
embodiments for fabrication of a TFB such as shown in FIGS. 1A
& 1B, which includes a three-dimensionally restructured
substrate surface. The process flow for fabricating a TFB may
include: providing a substrate (201); three-dimensionally
restructuring the surface of the substrate by a laser process (202)
to form a restructured substrate; depositing a cathode current
collector on the restructured substrate (203); depositing a cathode
layer on the cathode current collector (204); and depositing an
electrolyte layer on the cathode layer (205); wherein the interface
between the cathode layer and the electrolyte layer is a
three-dimensional surface roughly in conformity with the
three-dimensionally restructured surface of the restructured
substrate. The battery fabrication may be finished (206) with the
deposition of an anode, an anode current collector (ACC),
protective coating and electrical contacts, for example. As noted
above with reference to FIG. 1A, the electrolyte-anode and
anode-ACC interfaces may also be three-dimensional surfaces roughly
in conformity with the three-dimensionally restructured surface of
the restructured substrate when the electrolyte and anode
depositions are to the layers on which they are deposited.
[0024] Substrate materials that strongly absorb laser energy are
suitable for the process described above with reference to FIG. 2;
some example substrate materials are Si, Al, stainless steel, etc.
For these substrates a laser energy source is used to restructure
the nominally planar substrate surface to form three-dimensional
features on the surface. A laser process fluence (typically <2
J/cm.sup.2 depending on CCC material) is used which is lower than
the ablation threshold of the material but higher than the melting
threshold of the material--a typical fluence of less than 0.4
J/cm.sup.2 is used for Au. Laser irradiation of the substrate
surface with such fluence levels causes the formation of
three-dimensional features such as cone-shaped surface structures,
although the shape, height, and density of these three-dimensional
features can be controlled by adjusting laser process parameters
such as wavelength, fluence, pulse frequency, number of shots, etc.
A high power (for example >100 W) nanosecond pulse laser, or
even a microsecond pulse laser is typically used for this surface
restructuring process. A laser system for this process can be a
laser projection system with beam homogenizers, which is typically
designed for excimer lasers. In other embodiments the laser system
can be a laser scanning system with beam shapers configured to
deliver the laser energy uniformly on the sample surface. Lasers of
a wide range of types and operating wavelengths (such as IR
(infrared), green and UV) may be used according to some
embodiments. Suitable laser wavelengths and operating parameters
will depend, among other things, on the optical properties
(absorptivity vs, wavelength) of the materials undergoing laser
surface restructuring. For example, green lasers may be used to
cut/shape ceramic substrates, metals, mica, Si, etc., CO.sub.2
lasers may be used to scribe glass substrates, and it is expected
that UV lasers may also be able to mark/shape these substrates as
well.
[0025] FIG. 3 show an example of a TFB with a vertical stack
fabricated according to embodiments of the present disclosure with
a three-dimensionally restructured CCC surface. In FIG. 3, the
vertical stack comprises: a substrate 310; a restructured CCC 320
formed on the surface of the substrate, the surface of the CCC
having been three-dimensionally restructured; a cathode layer 330
deposited on the restructured CCC; an electrolyte layer 340
deposited on the cathode layer; an anode layer 350 deposited on the
electrolyte layer; and an ACC 360 deposited on the anode layer. It
should be noted that the interface between the cathode layer and
the electrolyte layer is a three-dimensional surface roughly in
conformity with the three-dimensionally restructured surface of the
restructured substrate. Furthermore, in some embodiments the
electrolyte-anode and anode-ACC interfaces may also be three
dimensional surfaces roughly in conformity with the
three-dimensionally restructured CCC surface. The TFB may also
include protective coating(s) and electrical contacts, for example.
The perspective view of FIG. 1A, described above, is representative
of the three-dimensionally restructured surface of the CCC; the
features of the restructured surface of the CCC are shown as
conically shaped features in FIG. 3, although the features of the
restructured substrate surface may be varied in size, shape,
spacing and arrangement from what is shown and may include
cylindrical features, trapezoidal features, spherical features and
randomly placed features, for example.
[0026] FIG. 4 provides a process flow, according to some
embodiments for fabrication of a TFB such as shown in FIG. 3, which
includes a three-dimensionally restructured CCC surface. The
process flow for fabricating a TFB may include: providing a
substrate (401); depositing a CCC on the restructured substrate
(402); three-dimensionally restructuring the surface of the CCC
(403) to form a restructured CCC; depositing a cathode layer on the
restructured CCC (404); and depositing an electrolyte layer on the
cathode layer (405); wherein the interface between the cathode
layer and the electrolyte layer is a three-dimensional surface
roughly in conformity with the three-dimensionally restructured
surface of the restructured CCC. The battery fabrication may be
finished (406) with the deposition of an anode, an anode current
collector (ACC), protective coating and electrical contacts, for
example. As noted above with reference to FIG. 3, the
electrolyte-anode and anode-ACC interfaces may also be
three-dimensional surfaces roughly in conformity with the
three-dimensionally restructured surface of the restructured
CCC.
[0027] The surface of the CCC may be restructured by a laser
process as described in more detail herein, or another process may
be used, such as mechanical roughening (e.g. bead blasting), plasma
processing and ion bombardment, for example. Note that some of
these other processes which are non-thermal may be suitable for
three dimensionally restructuring the cathode and/or electrolyte
surfaces, where the phase and crystallinity of the cathode and/or
electrolyte needs to be preserved.
[0028] Cathode current collectors are typically formed of metal
layers deposited to a thickness of about 0.5 microns or greater and
strongly absorb laser energy and are suitable for the process
described above with reference to FIG. 4; some example CCC
materials are Au or Pt with some adhesion layers, etc. For these
substrates a laser energy source is used to restructure the
nominally planar CCC surface to form three-dimensional features on
the surface. A laser process fluence (typically <2 J/cm.sup.2
depending on CCC material) is used which is lower than the ablation
threshold of the material but higher than the melting threshold of
the material--a typical fluence of less than 2 J/cm.sup.2 is used
for Ti and Au. Laser irradiation of the substrate surface with such
fluence levels causes the formation of three-dimensional features
such as cone-shaped surface structures, although the shape, height,
and density of these three-dimensional features can be controlled
by adjusting laser process parameters such as wavelength, fluence,
pulse frequency, number of shots, etc. A high power (for example
>100 W) nanosecond pulse laser, or even a microsecond pulse
laser is typically used for this surface restructuring process.
Note that this embodiment is well suited to TFBs formed on
transparent substrates such as glass, quartz, mica, etc., although
this embodiment is not limited to use with these substrates and
will work equally well for non-transparent substrates, for
example.
[0029] It should be noted that substrate and CCC surfaces can be
restructured using traditional mask imaging followed by wet and/or
plasma etch. However, this approach is only readily available for
use with a limited number of materials, such as silicon, for
example, and involves multiple steps and adds significant cost to
the fabrication of TFB products, when compared to the process of
the embodiments disclosed herein. Furthermore, laser restructuring
of LiCoO.sub.2 cathode layers prior to electrolyte deposition has
been evaluated by the inventors and it has been determined that
laser restructuring of LiCoO.sub.2 cathode layers results in phase
separation of the LiCoO.sub.2 layer into high temperature (HT) LCO
and Co.sub.3O.sub.4, which overall negatively affects battery
performance and as such is highly undesirable for thin cathode
TFBs. (The impurity phase Co.sub.3O.sub.4 is detrimental to battery
charge capacity and also to cycle life.)
[0030] An example of a cathode layer is a LiCoO.sub.2 layer, of an
anode layer is a Li metal layer, and of an electrolyte layer is a
LiPON layer. However, it is expected that a wide range of cathode
materials such as NMC (NiMnCo oxide), NCA (NiCoAl oxide), LMO
(Li.sub.xMnO.sub.2), LFP (Li.sub.xFePO.sub.4), LiMn spinel, etc.
may be used, a wide range of anode materials such as Si, Sn, C,
etc. may be used, and a wide range of lithium-containing
electrolyte materials such as LLZO (LiLaZr oxide, such as
Li.sub.7La.sub.3Zr.sub.2O.sub.12), LiSiCON, Ta.sub.2O.sub.5, etc.
may be used. Deposition techniques for these layers may be any
deposition technique that is capable of providing the desired
composition, phase and crystallinity, and may include deposition
techniques such as PVD (physical vapor deposition), reactive
sputtering, non-reactive sputtering, RF (radio frequency)
sputtering, multi-frequency sputtering, evaporation, CVD (chemical
vapor deposition), ALD (atomic layer deposition), etc. and when
non-vacuum techniques are applicable, may also include slot die
coating, plasma spray, spray pyrolysis, electroplating, slurry
based screening, etc.
[0031] FIG. 5 is a schematic illustration of a processing system
500 for fabricating a TFB, according to some embodiments. The
processing system 500 includes a standard mechanical interface
(SMIF) 501 to a cluster tool 502 equipped with a reactive plasma
clean (RPC) chamber 503 and process chambers C1-C4 (504, 505, 506
and 507), which may be utilized in the process steps described
above. A glovebox 508 may also be attached to the cluster tool. The
glovebox can store substrates in an inert environment (for example,
under a noble gas such as He, Ne or Ar), which is useful after
alkali metal/alkaline earth metal deposition. An ante chamber 509
to the glovebox may also be used if needed--the ante chamber is a
gas exchange chamber (inert gas to air and vice versa) which allows
substrates to be transferred in and out of the glovebox without
contaminating the inert environment in the glovebox. (Note that a
glovebox can be replaced with a dry room ambient of sufficiently
low dew point as such is used by lithium foil manufacturers.) The
chambers C1-C4 can be configured for process steps for
manufacturing TFBs which may include, for example: deposition of a
CCC on a substrate, followed by three dimensionally restructuring
the surface of the CCC by a laser process, followed by deposition
of a cathode layer on the restructured CCC surface, followed by
deposition of an electrolyte layer (for example UPON by RF
sputtering a Li.sub.3PO.sub.4 target in N.sub.2) on the cathode
layer, as described above. (Note that the three dimensional
restructuring may be done in a cluster tool as described herein, or
may be done in a stand alone tool.) Examples of suitable cluster
tool platforms include display cluster tools. It is to be
understood that while a cluster arrangement has been shown for the
processing system 500, a linear system may be utilized in which the
processing chambers are arranged in a line without a transfer
chamber so that the substrate continuously moves from one chamber
to the next chamber.
[0032] FIG. 6 shows a representation of an in-line fabrication
system 600 with multiple in-line tools 601 through 699, including
tools 630, 640, 650, according to some embodiments. In-line tools
may include tools for depositing all the layers of a TFB, and a
tool for three dimensionally restructuring the surface of one of
the substrate and CCC. Furthermore, the in-line tools may include
pre- and post-conditioning chambers. For example, tool 601 may be a
pump down chamber for establishing a vacuum prior to the substrate
moving through a vacuum airlock 602 into a deposition tool. Some or
all of the in-line tools may be vacuum tools separated by vacuum
airlocks. Note that the order of process tools and specific process
tools in the process line will be determined by the particular TFB
fabrication method being used, for example, as specified in the
process flows described above. Furthermore, substrates may be moved
through the in-line fabrication system oriented either horizontally
or vertically.
[0033] In order to illustrate the movement of a substrate through
an in-line fabrication system such as shown in FIG. 6, in FIG. 7 a
substrate conveyer 701 is shown with only one in-line tool 630 in
place. A substrate holder 702 containing a substrate 703 (the
substrate holder is shown partially cut-away so that the substrate
can be seen) is mounted on the conveyer 701, or equivalent device,
for moving the holder and substrate through the in-line tool 630,
as indicated. An in-line platform for processing tool 630 may in
some embodiments be configured for vertical substrates, and in some
embodiments configured for horizontal substrates.
[0034] Some examples of apparatus for fabricating TFBs according to
certain embodiments are as follows. An apparatus for manufacturing
TFBs according to some embodiments may include: a first system for
three-dimensionally restructuring the surface of a substrate to
form a restructured substrate surface; a second system for
depositing a first current collector (FCC) layer on the
restructured substrate surface; a third system for depositing an
electrode layer on the FCC layer; and a fourth system for
depositing an electrolyte layer on the electrode layer; wherein the
interface between the electrode layer and the electrolyte layer is
a first three-dimensional surface roughly in conformity with the
restructured substrate surface. The first system may comprise, for
example, a laser ablation patterning system, in embodiments an ion
sputtering system, and in embodiments a mechanical roughening
system (such as a bead blaster). Furthermore, in embodiments the
apparatus may further comprise: a fifth system for depositing a
second electrode layer on the electrolyte layer; wherein the fourth
system deposits the electrolyte layer, and wherein the interface
between the electrolyte layer and the second electrode layer is a
second three-dimensional surface roughly in conformity with the
restructured substrate surface. The systems may be cluster tools,
in-line tools, stand-alone tools, or a combination of one or more
of the aforesaid tools. Furthermore, the systems may include some
tools which are common to one or more of the other systems.
[0035] Another apparatus for manufacturing TFBs according to some
embodiments may include: a first system for depositing a first
current collector (FCC) layer on the surface of a substrate; a
second system for three-dimensionally restructuring the surface of
the FCC layer to form a restructured FCC surface; a third system
for depositing a first electrode layer on the restructured FCC
surface; and a fourth system for depositing an electrolyte layer on
the first electrode layer; wherein the interface between the first
electrode layer and the electrolyte layer is a first
three-dimensional surface roughly in conformity with the
restructured FCC surface. The second system may comprise, for
example, a laser ablation patterning system, in embodiments an ion
sputtering system, and in embodiments a mechanical roughening
system (such as a bead blaster). Furthermore, in embodiments the
apparatus may further comprise: a fifth system for depositing a
second electrode layer on the electrolyte layer; wherein the
interface between the electrolyte layer and the second electrode
layer is a second three-dimensional surface roughly in conformity
with the restructured FCC surface. The systems may be cluster
tools, in-line tools, stand-alone tools, or a combination of one or
more of the aforesaid tools. Furthermore, the systems may include
some tools which are common to one or more of the other
systems.
[0036] Although embodiments of the present disclosure have been
particularly described with reference to restructuring of either
the substrate or the CCC surface, further embodiments include
applying the same approach to directly restructuring one or more of
the different interfaces on the anode-side of the TFB after
electrolyte deposition. (This process may also be done in
combination with restructuring of substrate or CCC surfaces.) For
example, the surface of the electrolyte layer may be three
dimensionally restructured--this process may be suitable for
crystalline electrolyte materials such as LLZO.
[0037] Although embodiments of the present disclosure have been
particularly described with reference to TFB stacks with CCC
deposited on the substrate followed by cathode, electrolyte, anode,
and then ACC, further embodiments include using the same approach
for a TFB stack in which the ACC is deposited on the substrate
followed by anode, electrolyte, cathode and CCC, wherein the
substrate and/or ACC is three dimensionally restructured as
described above, and the surfaces of one or more subsequently
deposited layers will also be three dimensional surfaces roughly in
conformity with the three-dimensionally restructured substrate
and/or CCC surface.
[0038] Although embodiments of the present disclosure have been
particularly described with reference to TFBs, the principles and
teaching of the present disclosure may be applied to other
electrochemical devices, including energy storage devices
generally, and also to electrochromic devices. It should be noted
that in the case of electrochromic devices interface roughening may
lead to undesired diffuse scattering and a device with an
undesirable "hazy" appearance, although the roughened interface may
improve the device speed; for certain applications the trade-off
between optical quality and device speed may be worthwhile, and
furthermore the interface roughness may be designed to provide an
improvement in speed while not unduly degrading the optical
appearance.
[0039] Although embodiments of the present disclosure have been
particularly described with reference to TFBs with a first current
collector layer on the surface of a substrate, the principles and
teaching of the present disclosure may be applied to certain TFBs
without a current collector layer on the surface of the
substrate--for example, TFBs with electrically conductive
substrates. In embodiments a thin film battery may comprise: a
substrate comprising a substrate surface, wherein the substrate
surface is a first three-dimensional surface; a first electrode
layer deposited on the substrate, and an electrolyte layer
deposited on the first electrode layer; wherein the interface
between the first electrode layer and the electrolyte layer is a
second three-dimensional surface roughly in conformity with the
first three-dimensional surface. According to some embodiments, a
method of making the thin film battery may comprise: providing a
substrate; three-dimensionally restructuring the surface of the
substrate to form a restructured substrate surface; depositing an
electrode layer on the restructured substrate surface; and
depositing an electrolyte layer on the electrode layer; wherein the
interface between the electrode layer and the electrolyte layer is
a first three-dimensional surface roughly in conformity with the
restructured substrate surface. According to some embodiments, an
apparatus for manufacturing TFBs according to some embodiments may
include: a first system for three-dimensionally restructuring the
surface of a substrate to form a restructured substrate surface; a
second system for depositing an electrode layer on the restructured
substrate surface; and a third system for depositing an electrolyte
layer on the electrode layer; wherein the interface between the
electrode layer and the electrolyte layer is a first
three-dimensional surface roughly in conformity with the
restructured substrate surface.
[0040] Although embodiments of the present disclosure have been
particularly described with reference to certain embodiments
thereof, it should be readily apparent to those of ordinary skill
in the art that changes and modifications in the form and details
may be made without departing from the spirit and scope of the
disclosure.
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